Control system for charging of non/partially insulated superconducting magnets and related techniques
A system comprises a superconducting magnet comprising a coil of superconducting material. The coil includes electrical terminals. The windings of the coil are separated by a metallic conductor. A control circuit is coupled to the terminals to drive a current through the coil to charge the superconducting magnet and configured to provide a current through the coil that is sufficiently small to avoid a quenching effect of the superconducting magnet but also large enough to charge the magnet within a predetermined time period. A cooling structure is thermally coupled to the coil to remove heat caused by charging the superconducting magnet with the current to allow for the current to be sufficiently large to charge the magnet within the predetermined time period without causing the quenching effect.
1 . A system comprising:
a superconducting magnet comprising a coil of superconducting material, the coil comprising two electrical terminals, wherein windings of the coil are separated by a metallic conductor, wherein the superconducting magnet has no or partial electrical insulation between respective turns of the superconducting magnet;
a control circuit coupled to the two electrical terminals to drive a current through the coil to charge the superconducting magnet, and configured to provide a current through the coil that is sufficiently small to avoid a quenching effect of the superconducting magnet but also large enough to charge the superconducting magnet within a predetermined time period wherein the control circuit is configured to:
receive a sensed physical characteristic of the superconducting magnet from a sensor;
determine an electrical parameter to supply to the superconducting magnet based on the sensed physical characteristic and a model of the superconducting magnet stored in a computer-readable storage medium; and
provide the determined electrical parameter to the superconducting magnet having no or partial electrical insulation between respective turns of the superconducting magnet; and
a cooling structure thermally coupled to the coil to remove heat caused by charging the superconducting magnet with the current to allow for the current to be sufficiently large to charge the superconducting magnet within the predetermined time period without causing the quenching effect.
2 . The system of claim 1 wherein the cooling structure is configured to maintain a temperature of the coil at 4 deg K or higher.
3 . The system of claim 1 wherein the control circuit further comprises one or more feedback loops.
4 . The system of claim 3 wherein the one or more feedback loops feeds back a temperature of the coil.
5 . The system of claim 3 wherein the one or more feedback loops feeds back a current through the coil.
6 . The system of claim 3 wherein the one or more feedback loops feeds back a magnetic field of the coil.
7 . The system of claim 1 wherein the control circuit comprises a model of the coil.
8 . The system of claim 7 wherein the model comprises a temperature limit of the coil, a current limit of the coil, and a magnetic field limit of the coil.
9 . The system of claim 8 wherein the temperature limit, the current limit, and the magnetic field limit define a region within which the coil acts as a superconductor.
10 . The system of claim 1 , wherein the electrical parameter comprises the current and/or a voltage.
11 . An apparatus for controlling a superconducting magnet having no or partial electrical insulation between respective turns of the superconducting magnet, the apparatus comprising:
a control circuit for controlling a superconducting magnet having no or partial electrical insulation between respective turns of the superconducting magnet, the control circuit configured to:
receive a sensed physical characteristic of the superconducting magnet from a sensor;
determine an electrical parameter to supply to the superconducting magnet based on the sensed physical characteristic and a model of the superconducting magnet stored in a computer-readable storage medium; and
provide the determined electrical parameter to the superconducting magnet having no or partial electrical insulation between respective turns of the superconducting magnet.
12 . The apparatus of claim 11 , wherein the sensed physical characteristic comprises temperature, voltage, current, magnetic field and/or magnetic flux density.
13 . The apparatus of claim 11 , wherein the electrical parameter comprises a current and/or voltage.
14 . The apparatus of claim 11 , wherein the model represents a critical current of a superconductor of the superconducting magnet based on temperature, magnetic field and/or magnetic flux density.
15 . The apparatus of claim 11 , wherein the control circuit is further configured to:
after a time interval from the sensing of the physical characteristic, re-sense the physical characteristic;
re-determine, using a control circuit, the electrical parameter to supply to the superconducting magnet based on the re-sensed physical characteristic and the model; and
provide the re-determined electrical parameter to the superconducting magnet.
16 . The apparatus of claim 11 , wherein the determining comprises calculating a critical current of a superconductor of the superconducting magnet, calculating an error of the critical current with respect to a setpoint and setting the electrical parameter based on the error.
17 . The apparatus of claim 16 , wherein the calculating of the error comprises dividing a calculated current through the superconductor by the critical current to produce a ratio, and comparing the ratio to a setpoint.
18 . The apparatus of claim 11 , wherein the determining comprises calculating future parameters of the superconducting magnet based on the sensed physical characteristic, and setting the electrical parameter based on the calculated future parameters.
19 . The apparatus of claim 18 , wherein the model comprises a thermal model of the superconducting magnet.
20 . The apparatus of claim 11 , wherein the control circuit is configured to determine a degree of cooling based on the model and the sensed physical characteristic, and controlling a cooling system for the superconducting magnet based on the determined degree of cooling.